Power Supply

To provide 3.3V and 5V for the energy metering IC, processor, and radio to function, PowerCube employs an off-line inductorless switching regulator, the Supertex SR086. Without requiring high voltage capacitors, this device and its external components are low-volume, a key factor in its fitting into the cubic inch form factor. It also has a high enough current output, 100mA maximum, to power the energy metering IC and the radio at the same time.

In order to settle on the SR086, we first implemented and tested several low volume AC to DC power supplies. We studied these supplies based on volume, specifically how it scales with DC load power, and efficiency, the percent of total power that is delivered to the DC load.

Energy Metering

Processor and Radio

Based on the epic platform, PowerCube runs a Texas Instruments MSP430 processor and CC2420 radio.

These pictures show face 4, the processor and radio face. The two images shown are inside (left) and outside (right). For reasons of space, the MSP430 and CC2420 were placed on opposite sides of the board.